Checker-brick



Oct. 24, 1950 T. H. KENNEDY CHECKER-BRICK 4 Sheecs-Sheeo l Filed May 29, 1947 HI5 ATTORNEY.

Oct. 24, 1950 T. H. KENNEDY 2527,429

CHECKER-BRICK 4 Sheets-Sheet 2 Filed May 29, 1947 FIE-4- H15 ATTORN EY.

Oct. 24, 1950 -g KENNEDY 2,527429 CHECKER-BRICK Filed May 29, 1947 4 Sheets-Sheet 3 INVENTORI Patented Oct. 24, 1950 CHECKER-BBICK human H. Kennedy, Mclieesport, Pai, asslgnor to National Tube Company, a corporation o! New Jersey Application Muy 29, 1941, sei-m1 N0. 751,241

s Claims. (o1. 263-51) 'I'his invention relates to checkerbrick for hat blast stoves and the like.

Due to the conditions under which hot blast stoves operate, the checkerbrick tor ming the interior thereo1' are subjected to severe stresses and strains. This can be realized from the tact thai; such stoves are es larse as 22 It. in diameter und 115 1t. in height; moreover, the interior temperature ranges from 250 F. at the bottom to as much as 2500" F. a.t the top. Durlng operation of the stoves, there is a blast o! air passlng through the stoves at pressures cf about 18 lbs. per square inch. In addltlon to these internal physical conditions, the stoves are subject to extremes of outside atmospheric temperature und at times high winds. As a. result 013 these internal and external physical conditions, the stracture alternately contracts, expands a.nd thereby tends to twist and distort the refractory checkerbrick so that they lose their original alignment. Due to years 01' experience, lt has been amply demonstrated that the so-called basketweave :pattern of checkerbrlck is most conclucive to resisting this tendency to twist und distort the brick work from its original'alignment anti, ab

the Same time, provides the necessary strength to support the large mass o1 bricks.

The high temperatures ranging up to 2500 F. before noted. actually softens ab least the exposed surfaces of the refractory bricks ancl, i1 the brick is not sufflciently thick, the heat may penetrate the interior thereof suflciently to cause the brick to become completely -plastic and deformed. Accordingly the brlcks should. be 01 such thickness that the interior thereof will not become softened es a result 01' the high temperatures to which the surfaces or flue areas are exposed. In addition to the foregoing. consideration should be given to the provision 01 maximum heating surface consistent with the brick thickness. It is likewise desirable to have small flues for use with cleaned blast furnace gas in order to provide greater heat trans1'er efficiency.

It is accordingly an object 01 the present invention (so provide a form of checkerbrick that can be laid in basket-weave pattern to achleve maximum stability and which ab the Same tlme provides maximum heating suri'aces together with maximum hea.t transferring qualities without sacrifice of strength.

It is a turther object to provide a form 01 cheekerbrick which can be made by mol ding and which is eflicient am! economical in use.

The foregoing a.nd further objects will be apparenttrom the following specification when rea.d in conJunotion with the attached drawings, wherein:

Figure 1 is a planview, partly in section, of a hol: blast stove containing checkerwork formed 01 the checkerbrick o1 my invention;

Figure 2 is an isometric view of the preferred embodiment o1 my improved checkerbrick;

Figure 3 is an isometric view 01 basketweave checkerwork l'ormed from the checkerbrick shown in Figure 2;

Figure 4 is a. side elevatlon 01 the brick;

Figure 5 is a. vertical sectiou on line VV of Figure 4;

Flgure 6 is an enlarged plan 01 a section of checkerwork;

Figure 7 ls an enlarged plan o1 a section of checkerwork composed of a modifled form of checkerbrick; und

Figure 8 is an isometric view showing two of the bricks 013 Figure 7 in abutting relationship.

Referring more particularly to the drawings, the numeral 2 designates 'ohe preferred form of checkerbrick of my lnvention. The brick is substantially a rectangular parallelepiped having vertical concave end portions 4 which are in effect quarter segments o1 cylinders. A space 6 is provlded between the concave portions which is substantially equal to the thickness of the brick. The edges 8 01 the concave portions are relieved et angles of 45 relative bo the ends I0 of the bri6k or, in case o1 the inner edges 45 to a plane normal to the flat inner surfaces 6. Thus, when the bricks are lald in basket-weave pattern with the ends 01 the bricks abutting the fiat mid-surfaces 6 cf the adjacent brick, circular vertical flues I2 are formed.

T0 provide increased heating surfaces and heat transfer efiiciency, the flues I2 are provided with helical grooves I4. These grooves are in the form 01 double threads generated on the inside of a cylinder and are provided in the following manner. Euch of the concave surfaces 4 is provided with two groove segments IG which are quarter segments of a helix. These groove segments extend upwardly from left to right 011 both the freut und back surfaces of the brick at an angle of approximately 43 to the vertical axis of the brick. That is say the grooves start upwardly from left to right on the freut surface 01 the brick so that whichever surface is viewed the groove Segments are so disposed. Actually 1:0 achieve this eflect, the groove segments on the rear surface are oppositely lnclined with respect to the grdoves on the Iront surface. There are two groove segments on euch concave surface 3 and the upper left and lower.rlght band corners oi euch concave surl'ace are partlally grooved as als I8 to provlde smooth Junctures ot the groove segments when the brlcks are superpom in couventlonal baslret-weave pattern.

In a prel'erred slze, the brlck may be 9" long by 6" hlgh by 3" thlck. 'l'hls latter measwement ls extreme in thlckness a: measured lrom the unter tlps o! the concave Segments. At the mld-p'ortlon br mlnlmum thlckness, the brlck ls approxlmately 2" thlck. Thls forma flues approxlmately 3 in dlameter and wlth the grooves .728" deep by llu" wlde pro des 1005 square lnches 01 heatlng surface for auch cublc loot. cf stove volume. Wlthout the grooves, tl 1c clrcular flues would provlde only 634 square lnches cf heatlng surface. Tims. lt ls seen that the grooves result in a 58% lncrcaseln heatlng surface. Due to the groove; belng opposltely lncllned, thcbr-lcks are o ly anpreclably reduced in cross sectlon at the places where the grooves cross. Thls ls such a. small area that the ellect on the brlck strength ls negllglble.

Thls brlck can be readlly made by moldlng. By proi1ldlng drall; on the 81'00V, the mold and brlck can be separated as ls dem: in regular lron moldlng practlce. When lald in the lamlllar basket-weave 'pattern, the lateral grooVes form a serles 01 contlnuous hellces. ex-.

tendlng throughout the full lensth of the flues. The blast all passlng under pressure upwardly through the flues assumes a rotary splnnlng actlon conformlng to the hellcally grooved surfaces of sald flues. thus creatlng a contlnuous whlrlwlnd throughout each flue.

Slnce the alr splns whlle rlslng, lt contacts a much greater surface o1 the hol: relractory than when movlng through stralght smooth passages 01' flues. The eflect of thls rotary splnnlng actlon of the alr lntlrnately contactlng the heatlng surface o1. the flues ls to conslderably lncrease the transfer of heat from the refractory to the alr.

Llkewlse. a slmllar rotary splnnlng actlon lslmparted to the hot gases in thelr descent through the flues and an lncreased transfer 01 heat frorn the hot gases to the refractory ls attalned.

In Flgures 7 and 8, I have shown a modlficatlon of the checkerbrick o1 my lnventlon. Thls brlck deslgnated generally by the numeral 40 ls a. rectangular paralleleplped whlch ls lald in basket-weave pattern to form square flues 42. As in the preferred embodlment. a swlrlln or hellcal flow ls imparted 120 gas dlrected through the flues by hellcal-llke grooves 44. The brlcks 40 have grooved portlons 46, 48' on botb faces adjacent both enda thereof wlth a pla.ln intermedlateportlon48 an both faces. In laylng the brlck in basket-weave pattern, the ends of the brlck ahnt the mld-portiom 48 of adjacent brlcks. Bach 01' the groove portions has three grooves Eli, 52 and whlch slant upwardly from left bo rlght at an angle cf about 45 to the vertlcal throughout the major portlon thereof. Grooves 50 and 52 have a short portlon 58 adjacent the lntermedlate portlon 48 whlch is parallel to the longitudinal axls cf the brlck. It ls noted that Erooves of the left band face 46' are reversed wlth respect to those cf the rlght band face 46. That ls, lntermedlate groove 50 ls at the bottom and short groove 54 ls a1: the top on the lel't band corner whereas 54 ls at thebottnm and 50 at the top o1 the rlght band face. Thus. lt surface 46' and grooves were plvoted 180 around a plvot at the center polnt cf the brlcks', the arooves thereof would be dlrectly superposed over the grooves 01 face 46. The grooves an the rear laces are exactly opposltely lncllned wlth respect to those an the traut face so that lt the brlck ls plvoted on lts vertical axls, the face in front will appear the Same no matter whlch ot the two taces ls belng vlewed.

A preferred slze o! thls brlck ls 9" lang by 6" hlgh by 3" thlck. When lald in basket weave thls produce a 3" square llue 42. 'I'he grooves may be /4" wlde .by "/4" deep and spaced on 3" centers measured an the vertlcal. Euch groove makes one turn in 12". 'I'hls brlck provldes 1,157 square lnches cf heatlng surface for each cublc !oot o! stove volume, whereas the same brlck wlthout the 81'ooves provldes only 576 square lnches o1 heatlng surface per cublc foot of stove volume. Thus. the groove provlde a lncrease in heatlng surlace.

Whlle I have shown and descrlbed two speclflc embodlments 01' my lnventlcn. lt will be anderstood that these embodlments are merely for the purpose 01 lllustratloh and descrlptlon and that varlous other forma may be devlsed wlthln the scope o! my lnventlon as defined in the appended clalms.

I clalm:

1. A substantlally rectangular paralleleplpedlc checkerbrlck adapted to be lald in basket-weave pattern to Iorm vertlcal flues characterlzed by segmental slantlng grooves on the uprlght tront and back laces adjacent the ends thereof, the grooves in sald front and back l'aces belng oppositely lncllned, sald segmental grocves comblnlng t.o l'orm substantlally contlnuous hellcal grooves o! thc same rotatlon around all 01 sald flues.

2. A substantlally rectangular paralleleplpedlc checkerbrlck adapted to be lald in basket-weave pattern to form vertlcal flues, sald brlck havlng slanting segmental grooves adjacent the ends 01 front and back l'aces thereof, the grooves in sald 1'ront and back faces belng opposltely lncllned, the mld-portlon cf sald l'aces havlng uninterrupted surl'aces, the slze o1 sald unlnterrupted surfaces belng substantlally the same as the and faces ot the sald brlck, the a'ngularlty 01 the slant 01' sald segmental grooves belng such that substantlally contlnuous hellcal-llke grooves o! the same rotatlon are l'ormed thereby when sald brlck ls lald in basket-weave pattern.

3. A substantlally rectangular paralleleplpedlc checkerbrlck adapted to be lald in basket-weave pattem sald brlck havlng opposltely dlsposed vertlcally extendlng concave portlons on the l'ront and back laces adjacent both ends thereof, the surfaces of sald concave portlons comprls- Ing substantlally quadrants 02 a clrcle and flat portlons lntermedlate sald concave portlons, sald concave portlons combinlng to form clrcular flues when sald brlck ls lald in basket-weave pattern.

4. A substantlally rectangular parallelepipedlc checkerbrlck adapted be lald in basket-weave pattern, sald brlck havlng vertlcally dlsposed concave cyllndrlcal quarter segments on the l'ront and back faces adjacent both ends thereof, flat portions lntermedlate sald concave portlons. segmental grooves in sald concave portlons, sald grooves comblnlng to form contlnuous grooves around the flues Iormed by sald concave portlons when sald brlck ls lald in basket-weave pattern.

5. A substantlally rectangular parallelepipedic checkerbrick adapted to be lald lnbasket-weave pattern, sald brlck havlng vertlcally dlsposed edges 01 sa.id concave segments being beveled, l

flat portlons havlng uninterrupted surtaces intermediate said concave portions, angularly dis- -posed thread-like segmental grooves in said cancave segments, the groovs in said front and back faces being inclined in opposite directions, said segmental grooves combining 170 form substantially continuous thread-llke grooves around circular flues formed by sald concave segments when said brick is 1a1d in basket-weave pattern.

'I'RUMAN' H. KENNEDY.

REFERENCES CI'IED The fol1owing references are cf record in the file 01 t11is patent:

UNITED STATES PATENTS Number Name Date 1887,704 Wilisclc Nov. 15, 1932 2,126,095 Dean Aug. 9, 1938 FOREIGN PATENTS Number Country Dabe 242,083 Grea.t Brltaln Nov. 5, 1925 544,460 France June 22, 1922 631.762 France Sept. 20, 1927 729,312 France Am. 25, 1932 

